[PATCH] drm/i915/dg2: Add preemption changes for Wa_14015141709

[Matt Roper]

From: Akeem G Abodunrin <akeem.g.abodunrin at intel.com>

Starting with DG2, preemption can no longer be controlled using userspace
on a per-context basis. Instead, the hardware only allows us to enable or
disable preemption in a global, system-wide basis. Also, we lose the
ability to specify the preemption granularity (such as batch-level vs
command-level vs object-level).

As a result of this - for debugging purposes, this patch adds debugfs
interface to configure (disable/enable) preemption globally.

Jira: VLK-27831

Cc: Matt Roper <matthew.d.roper at intel.com>
Cc: Prathap Kumar Valsan <prathap.kumar.valsan at intel.com>
Cc: John Harrison <john.c.harrison at intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Signed-off-by: Akeem G Abodunrin <akeem.g.abodunrin at intel.com>
Signed-off-by: Matt Roper <matthew.d.roper at intel.com>
---
 drivers/gpu/drm/i915/gt/intel_gt_regs.h     |  3 ++
 drivers/gpu/drm/i915/gt/intel_workarounds.c |  2 +-
 drivers/gpu/drm/i915/i915_debugfs.c         | 50 +++++++++++++++++++++
 drivers/gpu/drm/i915/i915_drv.h             |  3 ++
 4 files changed, 57 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_gt_regs.h b/drivers/gpu/drm/i915/gt/intel_gt_regs.h
index 19cd34f24263..21ede1887b9f 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_regs.h
+++ b/drivers/gpu/drm/i915/gt/intel_gt_regs.h
@@ -468,6 +468,9 @@
 #define VF_PREEMPTION				_MMIO(0x83a4)
 #define   PREEMPTION_VERTEX_COUNT		REG_GENMASK(15, 0)
 
+#define GEN12_VFG_PREEMPTION_CHICKEN		_MMIO(0x83b4)
+#define   GEN12_VFG_PREEMPT_CHICKEN_DISABLE	REG_BIT(8)
+
 #define GEN8_RC6_CTX_INFO			_MMIO(0x8504)
 
 #define GEN12_SQCM				_MMIO(0x8724)
diff --git a/drivers/gpu/drm/i915/gt/intel_workarounds.c b/drivers/gpu/drm/i915/gt/intel_workarounds.c
index c014b40d2e9f..18dc82f29776 100644
--- a/drivers/gpu/drm/i915/gt/intel_workarounds.c
+++ b/drivers/gpu/drm/i915/gt/intel_workarounds.c
@@ -2310,7 +2310,7 @@ rcs_engine_wa_init(struct intel_engine_cs *engine, struct i915_wa_list *wal)
 			     FF_DOP_CLOCK_GATE_DISABLE);
 	}
 
-	if (IS_GRAPHICS_VER(i915, 9, 12)) {
+	if (HAS_PERCTX_PREEMPT_CTRL(i915)) {
 		/* FtrPerCtxtPreemptionGranularityControl:skl,bxt,kbl,cfl,cnl,icl,tgl */
 		wa_masked_en(wal,
 			     GEN7_FF_SLICE_CS_CHICKEN1,
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 747fe9f41e1f..40e6e17e2950 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -571,6 +571,55 @@ static int i915_wa_registers(struct seq_file *m, void *unused)
 	return 0;
 }
 
+static void i915_global_preemption_config(struct drm_i915_private *i915,
+					  u32 val)
+{
+	const u32 bit = GEN12_VFG_PREEMPT_CHICKEN_DISABLE;
+
+	if (val)
+		intel_uncore_write(&i915->uncore, GEN12_VFG_PREEMPTION_CHICKEN,
+				   _MASKED_BIT_DISABLE(bit));
+	else
+		intel_uncore_write(&i915->uncore, GEN12_VFG_PREEMPTION_CHICKEN,
+				   _MASKED_BIT_ENABLE(bit));
+}
+
+static int i915_global_preempt_support_get(void *data, u64 *val)
+{
+	struct drm_i915_private *i915 = data;
+	intel_wakeref_t wakeref;
+	u32 curr_status = 0;
+
+	if (HAS_PERCTX_PREEMPT_CTRL(i915) || GRAPHICS_VER(i915) < 11)
+		return -EINVAL;
+
+	with_intel_runtime_pm(&i915->runtime_pm, wakeref)
+		curr_status = intel_uncore_read(&i915->uncore,
+						GEN12_VFG_PREEMPTION_CHICKEN);
+	*val = (curr_status & GEN12_VFG_PREEMPT_CHICKEN_DISABLE) ? 0 : 1;
+
+	return 0;
+}
+
+static int i915_global_preempt_support_set(void *data, u64 val)
+{
+	struct drm_i915_private *i915 = data;
+	intel_wakeref_t wakeref;
+
+	if (HAS_PERCTX_PREEMPT_CTRL(i915) || GRAPHICS_VER(i915) < 11)
+		return -EINVAL;
+
+	with_intel_runtime_pm(&i915->runtime_pm, wakeref)
+		i915_global_preemption_config(i915, val);
+
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(i915_global_preempt_support_fops,
+			i915_global_preempt_support_get,
+			i915_global_preempt_support_set,
+			"%lld\n");
+
 static int i915_wedged_get(void *data, u64 *val)
 {
 	struct drm_i915_private *i915 = data;
@@ -765,6 +814,7 @@ static const struct i915_debugfs_files {
 	const struct file_operations *fops;
 } i915_debugfs_files[] = {
 	{"i915_perf_noa_delay", &i915_perf_noa_delay_fops},
+	{"i915_global_preempt_support", &i915_global_preempt_support_fops},
 	{"i915_wedged", &i915_wedged_fops},
 	{"i915_gem_drop_caches", &i915_drop_caches_fops},
 #if IS_ENABLED(CONFIG_DRM_I915_CAPTURE_ERROR)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 457bc1993d19..8c3f69c87d36 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1407,6 +1407,9 @@ IS_SUBPLATFORM(const struct drm_i915_private *i915,
 #define HAS_GUC_DEPRIVILEGE(dev_priv) \
 	(INTEL_INFO(dev_priv)->has_guc_deprivilege)
 
+#define HAS_PERCTX_PREEMPT_CTRL(i915) \
+	((GRAPHICS_VER(i915) >= 9) &&  GRAPHICS_VER_FULL(i915) < IP_VER(12, 55))
+
 static inline bool run_as_guest(void)
 {
 	return !hypervisor_is_type(X86_HYPER_NATIVE);
-- 
2.34.1